Mice transgenic for a human IL-6 gene are known in the art. However, random insertion of a human IL-6 transgene into the mouse genome results in poorly regulated expression of the human IL-6 protein, which manifests itself in a variety of pathologies in such transgenic mice, including, but not limited to, plasmacytosis and glomerulonephritis. As a result, these mice have limited usefulness.
There is a need for non-human animals, e.g., mice and rats, the express human or humanized IL-6 and/or human or humanized IL-6 receptor. There is a need for such humanized mice that do not exhibit one or more pathologies exhibited by transgenic hIL-6 mice.